This invention relates to continuously-repetitive quantity-metering devices, used for example in manufacturing and processing operations to repeatedly dispense precisely metered quantities of a media. The metering apparatus of the present invention can be used with a great many different particular types of media, but in a particularly desirable application the invention may be used for highly accurate positive-displacement volumetric metering of flowable baking dough or other food products in conjunction with elements of a "wire-cut machine". The wire-cut machine in its basic form is a machine which has for many years been a well-known apparatus in the baking trade.
Conventionally, the standard wire-cut dough metering machine uses counter-rotating feed rollers within a hopper, which force a continuous supply of baking dough downward through shaping orifices, with a cutting wire or knife being passed beneath each orifice at repeated time intervals, thereby slicing off a short cylindrical (or otherwise shaped) segment of the baking dough on each process cycle, representing an individual cookie or the like.
Conventional wire-cut dough metering machines have long been used in the baking trade, and to some extent in related fields, because such machines could produce food product deposits of fairly reasonably consistent sizes and weights. In the past, these machines were acceptable even though they provided what is now only a marginal degree of repetitive uniformity. In the past, this lack of repetitive uniformity could be compensated simply by operating the machine to produce larger deposits than required on the average. Thus, the probability of a particular deposit being underweight was reduced.
However, it is becoming increasingly necessary to provide much more accurate, repeatable metering dispensing devices by which each individual deposit weighs substantially the same as the other like deposits, in order to produce food more economically. It is not economically feasible simply to increase average product weight because of the increased costs of ingredients.
Therefore, there has been for some time a need for increasingly accurate, highly repeatable food volume depositors. The demand is not restricted necessarily to food depositors, but includes machines for other physically analogous media as well. There have been a number of fairly accurate volumetric depositor devices which employ a cylindrical rotating head with at least one piston passage therethrough. Each piston passage is oriented radially outwardly from the cylindrical head. The head rotates in a horizontally disposed cylindrical cavity. Media is fed into the top of the cavity. Metered quantities are ejected from the bottom of the cavity. Pistons reciprocate in the piston passageways so that media is sucked into the piston passageway when the passageway is in communication with the top of the cavity. The pistons eject media from the piston passageway when the piston passageways are in communication with the bottom of the cavity. For example, in U.S. Pat. No.2,815,573 to Trelease, entitled MANUFACTURE OF CHEESE SLICES, discloses a cheese slice-dispensing apparatus employing a rotary head having a plurality of molds and ejectors thereon for receiving charges of molten cheese and ejecting slices of cooled cheese.
Another example is shown in U.S. Pat. No. 4,212,609 to Fay, entitled METHOD AND APPARATUS FOR PRODUCING SHAPED AND SIZED FOOD ARTICLES. Fay employs a depositor roll having a plurality of ejectors thereon which alternately receive and eject discrete quantities of food. The rotary depositor roll is disposed beneath a pair of counter-rotating feed rolls which feed the media from a supply hopper. Vogt, U.S. Pat. No. 2,787,972 entitled APPARATUS FOR PRODUCING PLASTIC MASSES and U.K. Patent Specification No. 856,029 entitled METHOD AND APPARATUS FOR DIVIDING PLASTIC SUBSTANCES BY VOLUME disclose a similar food depositor wherein the cylindrical head has only one piston passage which extends completely through the head with two pistons therein. Because just two pistons are used, the design is believed to be particularly susceptible to extreme vibrations when high deposition rates are selected. The weight of the pistons will be shifted toward one side of the cylindrical head at two points during one rotation of the head.
One problem with such volumetric depositors is that dough or media often works its way past the pistons in the piston passageways clogging the actuating mechanisms which impart movement to the pistons in the piston passageways. This impairs the movement of the pistons in the passageways and makes the machine very difficult to clean. Furthermore, in food production, sanitation could be in jeopardy by the accumulation of food behind the pistons if the machine is not cleaned often enough.
Another problem with such depositors is that because each piston is at the bottom of its stroke when the piston is at the top of the cylindrical cavity, and at the top of its stroke when at the bottom of the cavity, the cylindrical head is always unbalanced about its axis of rotation. Thus, such depositors can shake violently if run at high deposition rates. Such shaking can cause mechanical failure of some parts, and is noisy.
In narrower aspects of this invention, a new method of food manufacture can be provided. Repetitive, accurately-metered, volumetric quantities of media ejected can be injected as pulses into a different ejection stream emanating from conventional extruder or like apparatus, to thereby obtain, in effect, wholly-encapsulated or embedded nugget-like deposits of one media within another, which may be wire-cut or otherwise separated between the embedded deposits to form separate, discrete blocks (i.e., units) of one media within another, as for example a filling material within an outer covering material.